1. Field of Invention
The present invention relates to a switchable compound laser working machine for performing both engraving and cutting operations.
2. Related Art
The basic working principle of conventional laser processing machines is to guide and focus laser beams on surfaces of objects to be engraved. The materials of the objects are gasified due to sudden increase of temperature when the focused laser beams are absorbed by the materials, so that the surfaces of the objects are indented. Thus the objective of engraving or cutting is achieved.
The process of engraving and cutting by utilizing laser is very simple, just like the printing on paper by using a computer and a printer. The only difference there-between is that, for printing, ink is printed on paper; as for laser engraving, laser is projected onto nearly all kinds of materials such as wood, acryl, plastic, metal, stone, etc.
However, currently available laser engraving and cutting machines can be classified into two types, that is, metal tube laser machines and glass tube laser machines. The metal tube laser machines have higher watts and prices and are suitable for engraving operation. The glass tube laser machines have lower watts and prices and are suitable for cutting operation. Therefore, metal tube laser machines are used to perform engraving while the glass tube laser machines are used to perform cutting. Accordingly, users need to use different machines for different purposes of engraving and cutting, which is inconvenient for the users. Besides, there are still other disadvantages, such as that much more space is required to place different machines and that the total cost is increased. In order to solve above problems, laser working machines with two laser tubes are developed. In these machines, a light-converging lens is provided at the cross point of the two laser beams respectively from the two laser tubes. As shown in FIG. 5, two glass tubes “a”, “b” and a light-converging lens “c” are illustrated. The lens “c” has one surface capable of reflection and the other surface capable of light transmission. Consequently, the laser beams from the two laser tubes “a”, “b” can be output via a common pathway to process objects. However, the light-converging lens is not suitable for all kinds of laser tubes because the lasers from different kinds of laser tubes possess different optical and physical properties and consequently have different transmission and reflection values after being in contact with the coated material on the surfaces of the light-converging lens “c”. As a result, it will decrease the output energy of the lasers from the machines. Moreover, the cost of the light-converging lens “c” is higher and may further increase the total cost of the machine. Therefore, the light-converging lens “c” is not suitable for all kinds of laser working machines with two laser tubes “a”, “b”.